Access log replay for load testing? Jmeter Pitfalls and Competitors

Question

Context

We wish to use "replay" web server access logs to generate load tests. JMeter had come to mind as I'd recently read blog posts about using jmeter in the cloud (e.g. firing up a number of Amazon EC2 instances to generate the load)

For years I had heard of JMeter's ability to replay access logs, but in reviewing this feature I found the following.

Access Log Sampler

• DOES:

  • recreate sessions, i.e. handle the jsessionId token (thought it tries to approximate sessions by IP address);

• DOES NOT:

  • handle POST data (even if you could configure apache/tomcat to write out post data to the access log, jmeter access log sampler only handles 'common' log format).

Post data would go a long way toward recreating actual load.

Additionally, the documentation describes the Access Log Sampler as "alpha code" even though it's 8 years old. It doesn't seem actively maintained. (That's longer than Gmail's beta.)

HttpPerf

Another blog post pointed me to the httpperf tool. I've started to read up on it:

• blog: http://www.igvita.com/2008/09/30/load-testing-with-log-replay/
• httpperf: http://code.google.com/p/httperf/

Summary

• What's the best way to generate load testing 'scripts' from real user data?
• What has worked best for you?
• Pros and cons of various tools?

Answer 1

JMeter + HTTP Raw Request + Raw Data Source for me works well